1. Field of the Invention
The present invention relates generally to mobile fluid storage tanks, and in particular, to mobile fluid storage tanks commonly known as frac-tanks used in the oil and gas industry.
2. Description of the Related Art
Mobile fluid storage tanks, commonly known as frac-tanks, are used in the oil and gas industry for storing and dispensing fluids at oil and gas well sites. Examples of such storage tanks are disclosed in U.S. Pat. Nos. 4,406,471, 5,653,469, and 5,957,500. These storage tanks are typically large heavy gauge steel tanks that are towed by truck from one site to another. These storage tanks are also sometimes used for environmental clean-up jobs and to hold fluids and chemicals at industrial sites.
Conventional frac-tanks have a fixed hitch assembly at a front end, a rear wheel suspension assembly at a rear end, and a tank body between the front and rear ends. The frac-tanks are normally designed to be towed only while they are empty, and to be rested flat upon the ground when they are in use for storing fluid at a well site or the like. To tow a conventional frac-tank, a truck having a winch is normally required to lift the front end of the tank so that the hitch structure can be coupled with a mating fifth wheel hitch of the truck. With the front end of the tank lifted, the rear wheels of the conventional frac-tank are engaged with the ground and support the rear end of the tank body above the ground for transport.
Conventional frac-tanks are inconvenient to move from one location to another because a special winch truck is required to lift the front of the tank for coupling with the truck, and such winch trucks are not always readily available at the job site. Also, conventional frac-tanks often must be made with shorter dimensions at the front end of the tank body to limit the height of the tanks during transport, thereby reducing the holding capacity of the tanks.
There is a need in the industry for an improved frac-tank that can be towed from one location to another using a conventional semi tractor, and that can be made with a larger storage capacity without exceeding the legal size limits for over-the-road transport.